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2016 AGM

Submitted by admin on Wed, 04/06/2016 - 13:52

PHOTO: Members of the executive of theTavistock and District Historical Society gather around to view the model skulls on display by guest speaker Dr. Paul Bartlett (seated left) following the Society’s Annual Meeting on Saturday, April 2nd. With him is Tim Mosher and standing from the left are Bob Rudy, Harry Lawry, Barb Matthies, Mary Nicklas, Sherrill Calder, Ed Pellow and Denise McLachlin. (Photo courtesy of the Tavistock Gazette)

It wasn’t the past 150 years of history that intrigued members of the Tavistock and District Historical Society at their 12th Annual General Meeting. It was prehistory - the past 150,000 years.

Dr. Paul Bartlett was the keynote speaker on Saturday, April 2, 2016 at Grace United Church where about 30 people gathered to hear his authoritative talk on tracing our ancestry using human genetics. Dr. Bartlett sent a cheek swab away to the National Geographic Society for analysis through their Geno 2.0 Next Generation Genographic Project for DNA (Deoxyribonucleic acid) testing. What he found out was astonishing as well as satisfying because of his early interest in human origins.

As a university student, Dr. Bartlett studied physical anthropology which looks at bones to determine the links between early humans and their descendants. His studies taught him that as far back as 3.5 million years, humankind was evolving. At around 1.8 million years ago they began using their hands to work with tools and carry food back to the home. It seems that as the brain grew, so did the development of speech for coordinating hunting and foraging as well as securing mates. He said there were two distinct species of humans at this time, as well as Neanderthals.

All this was learned through fossil evidence and he provided a large number of model “skulls” to show the evolution of man. His interest peaked in 2001 when he and his wife, Joan, travelled to South Africa where he attended a medical conference. While there he visited several archeological sites in an area designated as a UNESCO world heritage site known as “The Cradle of Humankind.” Here he met Mrs. Ples, a 2.5 million year old fossil, and Lucy, a 3.2 million year old fossil, both ape-like beings that are thought to have walked upright.

Visiting these sites was the culmination of many years of interest in human origins that began when Dr. Bartlett was doing a university project in 1974. At that tme, with the invention of the electron microscope, he found that scientist could look deeper into human cells. Here they could find chromosomes which carry our genetic material through 22 paired cells and a twenty-third pair containing the X-Y chromosome. “These patterns are virtually identical for people anywhere in the world,” he said. With this new found DNA testing, it is possible to create a family tree of peoples in the world descended from the first “Adam and Eve”.

Mitocondrial DNA is from the female and nuclear DNA is from the male. What scientists found was that DNA passed from mother to daughter is copied exactly. But once in a while, about every 5,000 years, an error occurs in the genetic code. These variations are called haplotypes. Now it is believed that there are about 36 different branches to the original DNA tree. The Bushman of southern Africa have the oldest mitochondrial DNA haplotypes found anywhere in the world. “Genetists use these genetic variations to reconstruct human history. And the message emerging from our DNA is clear,” Dr. Bartlett said. “Everyone alive today is either an African or a descendent of Africans.”

“Geneticists have determined that Eve lived about 150,000 years ago by counting the variations in DNA that have occurred. But the interesting thing is that at one time after that the human population suddenly shrunk quite dramatically. Genetic evidence indicates that our ancestors went through a bottleneck around 100,000 years ago as a point where the total population from whom we are all descended numbered no more than 500 people, perhaps as few as 50 people. A catastrophic event happened that slashed the human popula-tion to almost nothing. They were fortunate to survive,” he said.

Studies have shown that humans began fanning out across the globe about 70,000 years ago. The first principal migration was via Asia Minor into India and then Southeast Asia about 60,000 years ago and into Australia about 50,000 years ago. They reached Europe about 47,000 years ago and split into seven DNA groups.

Neanderthals are probably the best documented species of hominid on the planet traced back through fossil evidence. With DNA testing, it is thought that Neanderthals and humans split from their last common ancestor about 400,000 years ago. Neanderthals ended up in the colder settings of Eurasia and evolved in a forbidding world during the Ice Age. It is believed they finally disappeared about 30,000 years ago, having co-existed with humans over some time period. And because of interbreeding between humans and Neanderthals, it’s why Europeans have a small amount of Neanderthal DNA and Africans don’t.

But what enabled humans to survive? The answer is the eyed sewing needle. Not only did humans have the tools to find food, create fire and build shelters, but to fashion clothing and materials that keep our bodies adaptable to climate change.

“DNA is one of nature’s most amazing creations,” Dr. Bartlett said. That’s why he was intrigued to have his DNA tested. It turns out he is a Haplogroup U which is found in approximately 11% of native Europeans and is held as the oldest maternal haplogroup found in that region. National Geographic test results show that Dr. Bartlett’s group DNA also contains 2.3% Neanderthal.

As for the man’s nuclear DNA, “men pass their Y chromosome on to their sons. If a man does not have sons, his Y chromo-some dies with him.”

That means Dr. Bartlett’s nuclear DNA will continue for at least another two generations. He has four sons and 6 grandsons (and 4 granddaughters).